An electrical connector comprises a housing with at least one electrically conductive terminal mounted therein. The terminal is electrically connected to another circuit component, such as discrete wire or a conductive region on a circuit board. Connectors are employed in mateable pairs such that each terminal and the housing of one connector are mateable with a corresponding terminal and the housing in another connector.
The terminals of electrical connectors frequently are very small components that are stamped and/or formed from flat narrow strips of metal. The stamping and/or forming of the terminals is carried out to define a structure that will achieve a high normal contact force against a second terminal mated therewith for insuring a high quality electrical connection. If, for some reason, mated terminals do not exert a high normal contact force against one another, a high quality electrical connection may not be achieved.
The ability of the terminals in an electrical connector to exert high normal contact forces against a mated terminal can be affected by many factors. For example, in some instances, the locations of electrical connectors within an apparatus prevent accurate alignment of the connectors prior to or during mating. This may particularly be a problem where at least one connector in a mateable pair is mounted to a panel that prevents accurate visual alignment during mating. A technician attempting to blind mate improperly aligned panel mounted connectors may stop the mating in response to resistance generated by the improperly aligned connector housings. This may result in an incomplete connector mating, such that the terminals are not advanced into positions for exerting optimum normal contact forces against one another.
An attempt to mate improperly aligned connectors also may damage the small terminals therein or the housings. In particular, contact beams of the terminals typically are designed to resiliently deflect about a selected axis during normal mating. Improper alignment of terminals during mating can cause one or more contact beams to be overstressed, and thereby prevent the overstressed beam from resiliently returning toward an undeflected condition.
The prior art includes many panel mounted electrical connectors that are intended to float into proper alignment for mating. The prior art floatable panel mountable electrical connectors typically have cross-sectional dimensions that are less than the corresponding cross-sectional dimensions of the mounting aperture in the panel. Thus, these prior art connectors are able to move within the mounting aperture. Separation of these prior art connectors from the panel is prevented by flanges, washers, latches, or other such means defining cross-sectional dimensions that exceed the corresponding cross-sectional areas of the mounting aperture in the panel. It often is desirable to maximize the density of components on a panel. Thus space used by the float mechanism may be considered a design penalty that should be minimized.
Most prior art floating panel mountable connectors include biasing means for urging the connector back toward a central alignment in the mounting aperture of the panel. The centering means typically will define a separate structure from both the panel and the connector housing. However, the prior art does include floatable panel mountable connectors where the centering means is integral with the housing. Examples of prior art floatable panel mountable connectors with integral centering means include: U.S. Pat. No. 3,989,343 which issued to Lucius et al. on Nov. 2, 1976; U.S. Pat. No. 4,168,874 which issued to Weidler et al. on Sep. 25, 1979; U.S. Pat. No. 4,815,984 which issued to Sugiyama et al. on March 28, 1989; and, U.S. Pat. No. 4,840,584 which issued Cox on June 20, 1989.
Some of the above identified prior art floatable panel mountable connectors are urged generally back toward a central position in the mounting aperture of the panel after forces on the connector have been removed. However, most prior art connectors generally do not ensure that the connector will accurately return to a preferred rotational alignment relative to the mating axis of the connector. A very desirable floatable panel mountable connector capable of both transverse and rotational self-alignment is disclosed in co-pending application Ser. No. 470,482 which was filed by the inventors herein on Jan. 26, 1990 and which is assigned to the Assignee of the subject invention. The connector shown in co-pending application Ser. No. 470,482 includes a housing of generally rectangular cross-section with each wall of the housing being characterized by an array of deflectable panel engaging beams extending therefrom. A plurality of the beams in each such array may be centering beams which are disposed and dimensioned to exert centering and angular alignment forces against edge regions of the mounting aperture in the panel. At least one of the deflectable beams in each such array is a locking beam for lockingly engaging a surface of the panel. The disclosure of U.S. patent application Ser. No. 470,482 incorporated herein by reference.
A poor quality electrical connection may also occur if one or more terminals is not properly seated in its respective housing. The improper seating of a terminal in a housing may occur if the terminal is not fully inserted into the housing during the initial assembly of the connector or if the terminal is vibrated or pulled out of its fully seated condition during use of the connector. Failures of this type are a particular concern in the automotive industry where electrical components are subjected to vibration almost continuously during normal usage and are subjected to direct force during some maintenance. To avoid these problems, the automotive industry often requires connectors to be provided with terminal position assurance (TPA) components which are constructed to detect incomplete insertion of the terminals. The automotive industry also generally requires locking means for locking the terminal in the housing. For example many connectors include deflectable latches inside the connector housing to lockingly engage the terminal after complete terminal insertion. These deflectable terminal engaging latches generally perform well. However the injection molded housings are subject to "short shots" where an insufficient amount of plastic is injected into a portion of a mold cavity. "Short shots" can result in some terminal engaging latches being omitted or being inoperative. The internal disposition of the latches makes visual quality control inspection difficult.
Most prior art TPA components are mountable to the front mating face of the connector and include structure which extends rearwardly into the connector for cooperating with terminal locking beams in the housing. For example, U.S. Pat. No. 4,557,542 issued to Coller et al. on Dec. 10, 1985 and discloses a wedge-like TPA component that is mountable to the front mating face of the housing. The wedge of the TPA component of U.S. Pat. No. 4,557,542 is urged between a pair of forwardly cantilevered terminal locking beams on the housing. An inability to fully insert the TPA wedge of U.S. Pat. No. 4,557,542 is intended to indicate incomplete mounting of a terminal in the housing. Additionally, complete seating of the TPA component is intended to prevent the terminal locking beams on the housing from deflecting free of the terminals. A similar structure is shown in U.S. Pat. No. 4,714,437 which issued to Dyki on Dec. 22, 1987. The TPA component shown in U.S. Pat. No. 4,714,437 also is mounted to the front mating face of the housing and includes a wedge which is urgeable between non-locking cantilevered beams on the housing. The wedge of the TPA component shown in U.S. Pat. No. 4,714,437 is operative to urge the terminals into static non-deflectable locking means disposed on outer walls of the housing. Another similar front mounting TPA component is shown in U.S. Pat. No. 4,826,452 which issued to Sian et al. on May 2, 1989. TPA components that are mountable to the front mating face of the connector housings often are considered undesirable in that they can limit options for designing the mating interface of pairs of electrical connectors and the terminals mounted therein.
An extremely desirable rear mountable TPA component is shown in U.S. Pat. No. 4,776,813 which issued to Wilson et al. on Oct. 11, 1988 and which is assigned to the Assignee of the subject invention. The TPA component shown in U.S. Pat. No. 4,776,813 is frictionally retained in the rear end of the connector housing and includes a forwardly projecting wedge that is urgeable between a plurality of forwardly cantilevered terminal locking beams of the housing. The terminals are inserted through the TPA component and into locked positions on the housing. The TPA component is then advanced from its initial frictionally mounted position into a final locked position. An inability to advance the TPA component into the final locked position is indicative of an improperly seated terminal. Conversely, the complete advancement of the TPA component prevents further deflection of the forwardly cantilevered terminal locking beams, and thus positively assures locking of the terminals in the housings.
Another very effective TPA component is shown in co-pending U.S. patent application Ser. No. 314,992 which was filed by Colleran et al. on Feb. 24, 1989 and which also is assigned to the Assignee of the subject application. The TPA component depicted in co-pending U.S. patent application Ser. No. 314,992 also is rear mounted and includes a forwardly projecting wedge. The wedge is urged between a pair of rearwardly cantilevered terminal locking beams of the housing. The housing may further include a second outwardly disposed pair of forwardly cantilevered terminal locking beams.
Still another very desirable rearwardly mounted TPA component is depicted in co-pending U.S. patent application Ser. No. 07/506,315 which was filed by Fred Love Krehbiel on April 9, 1990 and which also is assigned to the Assignee of the subject invention. The connector housing shown in co-pending U.S. patent application Ser. No. 506,315 includes rearwardly cantilevered terminal positioning beams which function to urge terminals outwardly and into engagement with static locking ramps on the housing. The wedge of the TPA component is urgeable between the terminal positioning beams when all of the terminals of the connector are fully seated and locked.
In view of the above, it is an object of the subject invention to provide a floatable panel mountable electrical connector that is self-centering and rotationally self-aligning in the mounting aperture of the panel.
It is another object of the subject invention to provide a floatable panel mountable connection having polarization means for ensuring a specified rotational alignment of the connector to the panel.
A further object of the subject invention is to provide a floatable panel mountable connector that is securely lockable to a panel, but that is selectively removable therefrom.
An additional object of the subject invention is to provide a connector having improved terminal position assurance means and terminal locking means for achieving accurate positioning of the terminals and high quality electrical connection.
Yet another object of the subject invention is to provide an electrical connector having a TPA component that is selectively lockable in alternate preload and final seated positions on the rear of a housing and that requires intentional activation of the locking means to advance between the preload and final seated positions.